1. Field of the Invention
The present invention relates to a liquid lens, and more particularly to a liquid lens that constitutes an optical element for actively obtaining power.
2. Related Background Art
In recent years, a liquid lens has been developed as one of lenses that can change refractive power.
Japanese Patent Application Laid-Open No. 2007-225779 discloses a description on the principle of a liquid lens that changes refractive power using electrowetting. In addition, a technique is disclosed on an optical element that improves centering properties of a liquid that constitutes the liquid lens and stabilizes an optical axis. With the optical element described in Japanese Patent Application Laid-Open No. 2007-225779, two regions having affinities for two liquids that constitute the liquid lens are formed alternately and concentrically with the optical axis of the liquid lens, and thus a peripheral position of an interface of the liquids can be specified with high accuracy.
However, if an external force caused by vibration or the like is applied to the liquid lens using the technique disclosed in Japanese Patent Application Laid-Open No. 2007-225779, the peripheral position of the interface is moved on any of the two regions, which may reduce optical performance.
Further, also for a liquid lens that does not use the technique disclosed in Japanese Patent Application Laid-Open No. 2007-225779, stably holding a peripheral position of an interface is an important challenge for stably maintaining optical performance.